Location: Temperate Tree Fruit and Vegetable Research
Project Number: 2092-21220-003-041-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jul 1, 2026
End Date: Oct 30, 2027
Objective:
Identify potato germplasm with stable resistance to Potato mop-top virus. Potato accessions exhibiting consistent resistance across two independent screening systems will be identified and prioritized as candidate resistance sources for incorporation into breeding programs.
Approach:
To identify germplasm with stable resistance to Potato mop-top virus (PMTV), a diverse panel of potato accessions will be evaluated using a recombinant infectious clone–based inoculation platform at Colorado State University that allows controlled virus delivery independent of the vector. The germplasm panel includes diverse germplasm within the Solanum Petota clade. The panel will include 74 plant introductions (PIs) along with appropriate controls. Plants will be propagated from true potato seeds and multiple biological replicates will be evaluated for each genotype. Plants will be inoculated with the infectious clone using established delivery methods and maintained under controlled greenhouse conditions. Following inoculation, plant tissues will be sampled to assess virus accumulation and systemic movement. PMTV presence and viral load will be quantified using molecular diagnostic assays (quantitative polymerase chain reaction). This system will enable precise assessment of host responses to PMTV infection.
Accessions showing low virus accumulation or absence of infection will be classified as high-confidence resistance candidates and will be immediately introduced into tissue-culture to ensure that within line genetic diversity does not impact future screening results.
Following the initial germplasm screening, additional accessions from species demonstrating resistance will be selected for further evaluation using. The resulting resistant germplasm and screening framework will support breeding programs working to develop PMTV-resistant potato cultivars for the U.S. potato industry.